How natural hydrogen, hiding deep in the Earth, could serve as a new energy source

In the search for more, new and cleaner sources of energy, a largely untapped resource is emerging: natural hydrogen.

Unlike hydrogen produced from industrial processes, natural hydrogen forms through geological reactions that occur normally , meaning it costs nothing to make – though it costs some amount to extract – and does not emit any carbon dioxide or other human‑caused pollutants.

Today, hydrogen is used mainly , and to , which can be and . Emerging technologies are making hydrogen a viable , , and . Hydrogen demand around the world is projected to grow from around . Some of that supply could come from nature itself, as well.

To describe each source of hydrogen, , and the energy industry as a whole, use a . In general, “gray” and “blue” hydrogen are made by burning fossil fuels, with blue hydrogen incorporating technology that captures the carbon dioxide produced in the process to reduce emissions. “Green” hydrogen comes from renewable‑energy‑powered electrolysis, using electricity to split water into hydrogen and oxygen. “White” or “gold” hydrogen occurs naturally underground and can be extracted directly with minimal processing.

How natural hydrogen forms

Natural hydrogen originates from several geological processes. The most well‑studied mechanism is , a reaction where water interacts with iron‑rich rocks known as , releasing hydrogen gas.

Serpentinization occurs in , including ocean ridges and such as the in North America, a band of mostly igneous rocks with some sedimentary rocks mixed in, which extends from Minnesota through the Lake Superior region and southward toward Kansas.

Another process, , occurs in deep sedimentary basins when organic material decomposes under high temperatures, roughly 480 to 930 degrees Fahrenheit (250 to 500 degrees Celsius). These reactions can also produce hydrogen , such as methane or nitrogen.

Because these processes happen over millions of years, using natural hydrogen generally requires far less energy than human‑made methods such as electrolysis, which consumes roughly – enough to power an , and more than can provide. Natural hydrogen is already made – it just has to be collected.

The science and the search

Researchers and exploration companies are developing methods similar to those used in oil and gas exploration to locate potential hydrogen accumulations. They are looking at three types of geological formations:

1. Focused seepage, where hydrogen seeps naturally through cracks and faults. It tends to reach the surface and disperse quickly, .
2. Coal beds, , offer higher potential density but pose difficulties for extraction. The hydrogen must first be separated from the coal and then to the extraction point.
3. Reservoir‑trap‑seal systems, comparable to the , are considered the most promising for commercial production because they can concentrate large volumes of hydrogen in well‑defined, drillable structures. However, they remain largely unproven in practice: The basic idea is well established, and geologists have a good sense of where those formations might occur, but they still lack detailed data on how much hydrogen these formations actually contain and how easy it would be to extract.

Massive reserves – somewhere

The U.S. Geological Survey estimates there could be underground around the world. But only a is estimated to be recoverable, both technically and in terms of reasonable costs.

However, even 2% of that total would be on the planetand enough to meet projected demand for , even accounting for .

All of that reserve has built up over billions of years. The Earth naturally produces of natural hydrogen each year – less than 1% of the amount expected to be needed each year by 2050. But only a fraction of that is likely to be efficiently captured.

So geologic hydrogen is likely best viewed as a very large but ultimately finite source of low‑carbon energy that can substantially complement, but not replace, other energy sources, including various methods of producing hydrogen.

Global hot spots

Currently, only one hydrogen field, at Mali’s Bourakébougou village, produces natural hydrogen commercially, supplying to power the village.

However, the number of companies has increased rapidly, from , according to Rystad Energy and related .

Apart from that one field in Mali, in the United States, , and several .

In the U.S., in Kansas has confirmed subsurface hydrogen concentrations reaching more than 90% hydrogen and 3% helium. The higher the concentration of hydrogen, the more efficient and cost‑effective it is to recover. HyTerra is also exploring elsewhere in the .

Technical barriers

Transforming geological hydrogen into a commercial energy source presents tough scientific and technical challenges. Detecting and measuring hydrogen underground is difficult because of its and .

And if what’s found is low concentrations of hydrogen mixed with large amounts of other gases, it can be before it can be used.

Economics and efficiency

The economic promise of natural hydrogen lies in its simplicity.

Because geological processes already performed the production work, early estimates suggest that extraction costs could be for other – or possibly even less than that.

But those figures are based on the and may not represent future large‑scale performance. Producing enough to serve commercial demand will require .

As one leading research group noted, “.” It’s a careful exploration for scientific evidence that could lead, in time, to an abundant, carbon‑free and continuous energy source that complements .